SEM Image Observation Using an Electron Energy and Electron Take-off Angle Filtered Detector

Scanning electron microscopes (SEMs) are usually equipped with two types of detectors: secondary and backscattered electron detectors. The former produces secondary electron images (SEI) rich in topographic information[1, 2], whereas the latter produces backscattered electron images (BEI) rich in composition information[3]. Recently, however, a few other detectors have been installed in addition to these two types of conventional detectors. For example, four different detectors can be installed in a field emission SEM JSM-7800F: an upper electron detector (UED), an upper secondary electron detector (USD), a backscattered electron detector (BED), and a lower electron detector (LED). They allow to separate electron energy and take-off angle. Therefore, they help to observe specimen shape and structure on nano-scale[4]. On the other hand, they detect electrons having passed through the electromagnetic field of the objective lens, which changes actual energy and take-off angle ranges. Consequently, it is difficult to distinguish the image contrasts in accordance with physical properties. In this study, an electron detector was designed and experimentally manufactured to detect electrons emitted in a definite, variable range of energy and take-off angle.